Internal combustion engine



Jan. 18, 1966 R. EHRHARDT INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 1 Filed July 28, 1961 INVENTOR.

RICHARD EHRHARDT M (27 #W FIG I ATTORNEY-51 Jan. 18, 1966 R. EHRHARDT INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 2 Filed July 28 1961 INVENTOR.

RICHARD EHRHARDT BY duh i7 ATTOR EYS United States Patent 3,229,673 j INTERNAL COMBUSTION ENGINE Richard Ehrhardt, Stuttgart-Unterturkheim, Germany,

assignor to Daimler-Benz Aktiengesellschaft, Stuttgart- Unterturkheim, Germany Filed July 28, 1961, Ser. No. 127,615 Claims priority, application Germany, July 30, 1960, D 33,913 14 Claims. (Cl. 123-8) The present invention relates to a rotary-piston internal combustion engine of trochoidal construction provided with a polygonal piston having at its corners sealing strips or sealing ledges.

With internal combustion engines of this type there have been noticed in practical operation thereof at the engaging or cam surfaces of the piston within the housing, especially in proximity to the constrictions in the trochoidally shaped engaging surface, periodic wear marks which apparently are due to the fact that the sealing strips or ledge members of the piston which slide along the exposed engaging surface, are thrown during operation of the engine under the influence of accelerating forces at first radially inwardly toward the piston and subsequently radially outwardly against the engaging surface within the housing.

By the use of the present invention which essentially consists in providing within the piston hydraulic dampening arrangements cooperating with the sealing strips which dampen movements of the sealing strips radially inwardly, movements of the sealing strips in the radially inward direction are practically prevented under consideration of the timely brevity of the operation thereof so that no movements directed radially outwardly can occur also in the absence of movements directed radially inwardly.

The dampening installations according to the present invention may consist essentially of pistons which are slidingly arranged in cylinders provided with throttle bores for the hydraulic dampening medium displaced by the piston and possibly also with venting bores.

According to the present invention, two dampening arrangements may be advantageously provided for each sealing strip.

Accordingly, it is an object of the present invention to provide a rotary-piston internal combustion engine of the type described hereinabove which effectively eliminates, by simple means, the shortcomings of the prior art constructions.

It is another object of the present invention to provide dampening installations for rotary piston internal combustion engines which are operative, by dampening radially inwardly directed movements of the sealing strips of the piston, to prevent periodically recurring wear in the surfaces of the walls with which cooperate the seals placed into the corners of the pistons.

A further object of the present invention resides in the provision of hydraulic dampening mechanisms for the sealing strips provided near the corners of polygonal pistons used in rotary piston internal combustion engines of trochoidal construction, which dampening mechanisms are simple in construction, involve relatively few parts and are readily accessible for servicing from the sides of the piston. 7

These and other objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, two dampening arrangements according to the present invention, and wherein:

FIGURE 1 is a partial cross sectional view through a 3,229,673 Patented Jan. 18, 1966 corner of a piston of an internal combustion engine of the type described hereinabove which is provided with radially disposed hydraulic dampening means for the sealing strips in accordance with the present invention,

FIGURE 2 is a partial cross sectional view, similar to FIGURE 1, of a modified embodiment of a dampening arrangement in accordance with the present invention having an axially disposed dampening means,

FIGURE 3 is a cross sectional view of an internal combustion engine in which a polygonal piston is arranged within a housing of trochoidal construction,

FIGURE 4 illustrates a detailed portion of the shaft provided in the arrangement of FIGURE 3,

FIGURE 5 illustrates a partial cross sectional view taken at right angle to FIGURE 4 through the internal combustion engine, and

FIGURE 6 is a partial cross sectional view taken at right angle to FIGURE 4 through the internal combustion engine and along a section spaced from that of FIG- URE 5.

Referring now to the drawing wherein like reference numerals are used throughout the two views to designate corresponding parts, and more particularly to FIGURE 1, reference numeral 1 designates therein the polygonal rotary piston of the internal combustion engine which is provided along the corner cooperating with the engaging surface 2 within housing 3 with an axial groove 4 in which the sealing strip or sealing ledge 5 is arranged that is radially movable. Two hydraulic dampening arrangements generally designated by reference numeral 6 are arranged inside of piston 1 within the hollow spaces 8 and are readily accessible from the sides of piston 1 through the closure plugs 7. The dampening arrangements 6 serve for purposes of dampening movements of the sealing strip 5 in the radial direction. For that purpose, each dampening arrangement 6 essentially consists of a piston 10 slidingly arranged within a respective cylinder 9. A rod 11 connected with the piston 10 extends through the bore 12 u to and into the axial groove 4 where it rests against the sealing strip 5. The passage of the rod 11 through the bore 12 is sealed off by means of the elastic ring 13 which is forced against the sealing place under the influence of spring 14, itself supported at the piston 10. The cylinder space disposed below the piston 10 is in communication with the space 8 by means of bore 15. Further, the cylinder space is additionally in communication with the venting bore 18 through the venting notch 16 and the annular space 17. The venting bore 18 leads to the radially disposed return bore 20 which interconnects the spaces 8 through the axial bore 19. The supply through suitable duct or pipe means of the dampening medium which simultaneously serves as cooling medium for the piston 1 may be of any conventional construction and, therefore, is not illustrated herein.

During operation of the internal combustion engine, there exists a continuous oil circulation within the spaces 8 which proceeds from the oil supply (not shown) of any conventional construction through the spaces 8 into the return bore 20. The cylinder spaces below the pistons 10 are thereby always filled with oil. If now a radially inwardly directed movement is imparted to the sealing strip 5 by reason of the occurring accelerating forces, there takes place a dampening of this movement by reason of the fact that the pistons 10 have to displace the oil present within the cylinder spaces through the bore 15 and to a very slight extent also through the venting notch 16. Since this action, namely the occurrence of the radially inwardly directed movement, is extremely brief time-wise, the movement of the sealing strip 5 radially inwardly is stopped for all practical purposes so that with a subsequent change in the direction of the accelerating forces 3 the sealing strip cannot be thrown against the engaging surface 2 radially outwardly.

In the embodiment illustrated in FIGURE 2, the sealing strip 5 is supported by rods 11 which are operatively connected through hell cranks 21 with the pistons 10. Both pistons are arranged together Within the cylinder 9 disposed axially within the rotary piston l of the internal combustion engine whereby the cylinder space of cylinder 9 disposed between the two pistons 10 is in communication with spaces 8 through the throttling bore 15. Otherwise, the operation of the embodiment illustrated in FIGURE 2 corresponds to that of the embodiment illustrated in FIGURE 1.

Looking now to FIGURES 3-6, FIGURE 3 shows, in cross sectional view and in a somewhat schematic manner, an internal combustion engine in which a polygonal piston 1 is arranged within a housing 3 of trochoidal construction. At the corners of the piston 1 are provided, within grooves 4, the sealing ledge members 5, controlled in accordance with the instant invention.

FIGURE 4 illustrates the shaft 25 of the engine provided with the eccentric 26 whereby the shaft is provided with an axial bore 27 terminating in a radial bore portion 27' for the supply of lubricating and/or cooling medium while the radial bore portion 30' together with the axial bore 30 serve for the discharge or removal of the lubricating and/or cooling medium.

FIGURE 5 illustrates a partial cross sectional view taken at right angle to FIGURE 4 through the internal combustion engine within the area of the radial discharge bore portion 27 while FIGURE 6 illustrates a similar cross sectional view taken within the area of the bore portion 30'.

While I have shown and described two embodiments in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of many changes and modifications within the spirit and scope thereof, and I therefore do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims. It should be noted that in the appended claims the cooling and lubricating means referred to therein are descriptive of dilferent aspects of the same disclosed device.

I claim:

1. In a rotary piston internal combustion engine of trochoidal construction having polygonal piston means provided with sealing meansat the corners thereof freely movably positioned in the radial direction of said polygonal piston means, the improvement essentially consisting of a hydraulic damping arrangement within said piston means and operatively connected with said sealing means, to dampen movements of said sealing means radially inwardly, said damping arrangement comprising cylinder means and sliding piston means within said cylinder means being disposed substantially radially with respect to the axis of said polygonal piston means including hydraulic pressure medium supplied to said cylinder means on both sides of said sliding piston means, said medium being at substantially equal pressure, said sliding piston means being operatively connected with said sealing means, and throttle bore means for the hydraulic pressure medium displaced by said piston means, said throttle bore means effectively interconnecting the cylinder space portion of said cylinder means on either side of said sliding piston means, said throttle bore further constituting the discharge aperture for said hydraulic pressure medium displaced by said sliding piston means during the radially inward movements of said sealing means.

2. In .a rotary piston internal combustion engine of trochoidal construction having polygonal piston means provided with sealing means at the corners thereof, the improvement essentially consisting of a hydraulic damping arrangement within said piston, means and operatively connected with said sealing means, to dampen movements of said sealing means radially inwardly, each damping arrangement being disposed substantially radially with respect to the axis of said polygonal piston means and comprising cylinder means and sliding piston means within said cylinder means, rod means extending 'i through passages provided within said polygonal piston. means and operatively connecting said sliding piston means with said sealing means, and throttle bore means for the hydraulic pressure medium displaced by said piston means, said throttle bore means being effectively in communication with the cylinder space portion within said cylinder means containing the hydraulic pressure medium displaced by said piston means during radially inward move-.

ments of said sealing means and constituting the discharge aperture for such hydraulic pressure medium.

3. In a rotary piston internal combustion engine of trochoidal construction having polygonal piston means provided with sealing means at the corners thereof, the improvement essentially consisting of a hydraulic damping arrangement within said piston means and operatively connected with said sealing means, to dampen movements of said sealing means radially inwardly, each damping arrangement being disposed substantially radially with respect to the axis of said polygonal piston means and comprising cylinder means and sliding piston means within said cylinder means, rod means extending through passages provided within said polygonal piston means and operatively connecting said sliding piston means with said sealing means, sealing ring means for said passages, compression spring means resting, on the one hand, against said sliding piston means to springload the sliding piston means in the damping direction thereof and, on the other, against said sealing ring means to urge the sealing ring means into sealing engagement with respect to said passages, and throttle bore means for the hydraulic pressure medium displaced by said piston means, said throttle bore means being effectively in communication with the cylinder space portion within said cylinder means containing the hydraulic pressure medium displaced by said piston means during radially inward movements of said sealing means and constituting the discharge aperture for such hydraulic pressure medium.

4. In a rotary piston internal combustion engine of trochoidal construction having polygonal piston means provided with sealing means at the corners thereof, the improvement essentially consisting of a hydraulic damping arrangement within said piston means and operatively connected with said sealing means, to dampen movements of said sealing means radially inwardly, each damping arrangement comprising two reciprocable pistons movable in mutually opposite directions, a common cylinder for said two reciprocable pistons, said cylinder being disposed essentially parallelly to the axis of rotation of said polygonal piston means, throttle bore means for the hydraulic pressure medium displaced by said pistons, said throttle bore means being effectively in communication with the cylinder space portion of said cylinder containing the hydraulic pressure medium displaced by said pistons during radially inward movements of said sealing means, and means operatively connecting said pistons with said sealing means including rods and bell-cranks.

5. In a rotary piston internal combustion engine of trochoidal construction having polygonal piston means provided with sealing means at the corners thereof, the improvement essentially consisting of a hydraulic damping arrangement within said piston means and operatively connected with said sealing means, to dampen movements of said sealing means radially inwardly, each damping arrangement comprising two reciprocable pistons movable in mutually opposite directions, a common cylinder for said two reciprocable pistons, said cylinder being disposed essentially parallelly to the axis of rotation of said polygonal piston means, throttle bore means. for the hydraulic pressure medium displaced by said pistons, said throttle bore means being effectively in communication with the cylinder space portion of said cylinder containing the hydraulic pressure medium displaced by said pistons during radially inward movements of said sealing means, and means operatively connecting said pistons with said sealing means including rods and bell-cranks, said rods extending through passages provided within said polygonal piston means, and spring-loaded sealing ring means for sealing said passages.

6. A rotary piston internal combustion engine of trochoidal construction having a polygonal piston and sealing ledge means at each corner of said polygonal piston, comprising damping means within said piston operatively connected with said sealing ledge means for damping radially inwardly directed movements of said sealing ledge means, said damping means including cylinder means, piston means slidingly arranged substantially radially with rspect to the axis of said polygonal piston means within said cylinder means and operatively connected with said sealing ledge means, means for supplying a fluid pressure medium at essentially constant pressure to said cylinder means and throttling bore means for receiving the fluid pressure medium displaced in said cylinder means by said piston means during radially inwardly directed movements of said sealing ledge means.

7. A rotary piston internal combustion engine of trochoidal construction having a polygonal piston provided with hollow spaces and with sealing means at each corner of said polygonal piston, comprising damping means within the hollow spaces of said piston operatively connected with said sealing means for damping radially inwardly directed movements of said sealing means, said damping means including cylinder means, piston means slidingly arranged within said cylinder means and operatively connected with said sealing means, and a circulatory system for a cooling medium operative to cool said piston including said hollow spaces and throttling bore means effectively providing a communication between said hollow spaces and said cylinder means whereby the cooling medium displaced in said cylinder means by said piston means during radially inwardly directed movements of said sealing means is throttled by said throttling bore means.

8. A rotary piston internal combustion engine of trochoidal construction having a polygonal piston provided with hollow spaces and with sealing means at each corner of said polygonal piston, a drive shaft operatively connected with said piston, and damping means within the hollow spaces of said piston operatively connected with said sealing means for damping radially inwardly directed movement of said sealing means, said damping means including cylinder means, piston means slidingly arranged within said cylinder means and operatively connected with said sealing means, and a circulatory lubricating system for supplying a lubricant to said engine drive shaft including supply means for supplying said lubricant, throttling bore means in communication with said cylinder means, and further bore means effectively connecting said throttling bore means with said supply means to provide displacement of said lubricant from said cylinder means by said piston means through said throttling bore means during inwardly directed movements of said sealing means.

9. A rotary piston internal combustion engine of trochoidal construction having a polygonal piston provided with hollow spaces and with means at each corner of said polygonal piston, a drive shaft operatively connected with said piston, and damping means within the hollow spaces of said piston operatively connected with said sealing means for damping radially inwardly directed movement of said sealing means, said damping means including cylinder means, piston means slidingly arranged within said cylinder means and operatively connected with said sealing means, removable closure plug means along the sides of said piston for said hollow spaces to enable access thereto from the sides of said piston and a circulatory lubricating system for supplying a lubricant to said engine drive shaft including supply means for supplying said lubricant, throttling bore means in communication with said cylinder means, and further bore means effectively connecting said throttling bore means with said supply means to provide displacement of said lubricant from said cylinder means by said piston means through said throttling bore means during inwardly directed movements of said sealing means.

10. A rotary piston internal combustion engine of trochoidal construction having a polygonal piston provided with hollow spaces and with sealing means at each corner of said polygonal piston, a drive shaft operatively connected with said piston, and damping means within the hollow spaces of said piston operatively connected with said sealing means for damping radially inwardly directed movement of said sealing means, said damping means including cylinder means, piston means slidingly arranged within said cylinder means and operatively connected with said sealing means, removable closure plug means along the sides of said piston for said hollow spaces to enable access thereto from the sides of said piston and a circulatory lubricating system for supplying a lubricant to said engine drive shaft including supply means for supplying said lubricant, throttling bore means in communication with said cylinder means, and further bore means effectively connecting said throttling bore means with said supply means to provide displacement of said lubricant from said cylinder means by said piston means through said throttling bore means during inwardly directed movements of said sealing means, the supply of said lubricant to the piston spaces within said cylinder means taking place by said supply means at radially outwardly disposed places.

11. A rotary piston internal combustion engine of trochoidal construction having a polygonal piston provided with hollow spaces and with sealing means at each corner of said polygonal piston, a drive shaft operatively connected with said piston, and damping means within the hollow spaces of said piston operatively connected with said sealing means for damping radially inwardly directed movement of said sealing means, said damping means including cylinder means, piston means slidingly arranged within said cylinder means and operatively connected with said sealing means, removable closure plug means along the sides of said piston for said hollow spaces to enable access thereto from the sides of said piston and a circulatory lubricating system for supplying a lubricant to said engine drive shaft including supply means for supplying said lubricant, throttling bore means in communication with said cylinder means, and further bore means effectively connecting said throttling bore means with said supply means to provide displacement of said lubricant from said cylinder means by said piston means through said throttling bore means during inwardly directed movement-s of said sealing means, the supply of said lubricant to the piston spaces within said cylinder means taking place by said supply means at radially outwardly disposed places, and venting bore means operatively connecting said piston spaces with said supply means at radially inwardly disposed places.

12. In a rotary piston internal combustion engine of trochoidal construction having a polygonal piston provided with a hollow space and with sealing means at the corners thereof, the improvement essentially consisting of a hydraulic damping arrangement within the hollow space of said piston and operatively connected with said sealing means, to dampen movements of said sealing means radially inwardly, said damping arrangement comprising cylinder means and sliding piston means within said cylinder means, said sliding piston means being operatively connected with said sealing means, and means for supplying a hydraulic pressure medium of essentially constant pressure to said hollow space on both sides of said sliding piston means including throttle bore means providing a communication between said supply means and the cylinder space Within said cylinder means and operative to throttle the hydraulic pressure medium displaced from said cylinder means by said piston means.

13. A hydraulic damping arrangement for damping radial movements of the seal means provided in the piston corners of a rotary-piston internal combustion engine, comprising cylinder means within the rotary piston, piston means slidable within said cylinder means and operatively connected with the seal means, and means including a hydraulic medium of essentially constant pressure within said cylinder means on both sides of said piston means for damping the movements of the seal means in the radially inward direction thereof.

14. A hydraulic damping arrangement for damping the seal means provided at the corners of a polygonal piston of a rotary-piston internal combustion engine of trochoidalconstruction, comprising cylinder means within the piston, piston means slidably received within the cylinder means and operatively connected with the seal means, means providing a hydraulic pressuremedium of essentially constant pressure within the cylinder means on both sides of said piston means to dampen, radially inw-ardly directed movements of the seal means including throttling bore means effectively establishing a communication with, the cylinder space portion of the, cylinder means containing the hydraulic pressure medium which is displaced by the piston means during radially inward movement of the seal means and constituting the .discharge aperture for such hydraulic pressure medium.

References Cited by the Examiner SAMUEL LEVINE, Primary Examiner.

RALPH H. BRAUNER, JOSEPH H. BRANSON, JR.,

KARL J. ALBRECHT, Examiners. 

1. IN A ROTARY PISTON INTERNAL COMBUSTION ENGINE OF TROCHOIDAL CONSTRUCTION HAVING POLYGONAL PISTON MEANS PROVIDED WITH SEALING MEANS AT THE CORNERS THEREOF FREELY MOVABLY POSITIONED IN THE RADIAL DIRECTION OF SAID POLYGONAL PISTON MEANS, THE IMPROVEMENT ESENTIALLY CONSISTING OF A HYDRAULIC DAMPING ARRANGEMENT WITHIN SAID PISTON MEANS AND OPERATIVELY CONNECTED WITH SAID SEALING MEANS, TO DAMPEN MOVEMENTS OF SAID SEALING MEANS RADIALLY INWARDLY, SAID DAMPING ARRANGEMENT COMPRISING CYLINDER MEANS AND SLIDING PISTON MEANS WITHIN SAID CYLINDER MEANS BEING DISPOSED SUBSTANTIALLY RADIALLY WITHIN RESPECT TO THE AXIS OF SAID POLYGONAL PISTON MEANS INCLUDING HYDRAULIC PRESSURE MEDIUM SUPPLIED TO SAID CYLINDER MEANS ON BOTH SIDES OF SAID SLIDING POSITION MEANS, SAID MEDIUM BEING AT SUBSTANTIALLY EQUAL PRESSURE, SAID SLIDING PISTON MEANS BEING OPERATIVELY CONNECTED WITH SAID SEALINGNG MEANS, AND THROTTLE BORE MEANS FOR THE HYDRAULIC PRESSURE MEDIUM DISPLACED BY SAID PISTON MEANS, SAID THROTTLE BORE MEANS EFFECTIVELY INTERCONNECTING THE CYLINDER SPACE PORTION OF SAID CYLINDER MEANS ON EITHER SIDE OF SAID SLIDING PISTON MEANS, SAID THROTTLE BORE FURTHER CONSTITUTING THE DISCHARGE APERTURE FOR SAID HYDRAULIC PRESSURE MEDIUM DISPLACED BY SAID SLIDING PISTON MEANS DURING THE RADIALLY INWARD MOVEMENTS OF SAID SEALING MEANS. 